Aug. 29, 2011 (Paris) -- Chocoholics have reason to celebrate today: A large new study confirms that chocolate may be good for the heart and brain.

Regularly eating chocolate could cut the risk of heart disease and stroke by about one-third, says researcher Oscar H. Franco, MD, PhD, of the University of Cambridge in the U.K.

But before you indulge, a cautionary note: Chocolate bars, cookies, and drinks are high in sugar, fat, and calories, so eating too much can lead to weight gain and, you guessed it, heart disease. "Moderation is key," Franco tells WebMD.

Chocolate Linked to 37% Lower Risk of Heart Disease

Previous studies have suggested that chocolate may protect against high blood pressure and diabetes, both of which are risk factors for heart disease and stroke.

But no large-scale study has ever looked at whether chocolate actually reduces the risk of heart disease, Franco says.

So he and colleagues pooled the results of seven published studies involving more than 100,000 people that explored the association between chocolate and heart disease and strokes.

Results showed that people who ate the most chocolate had a 37% lower risk of heart disease and a 29% lower risk of stroke compared with people who ate the least amount of chocolate.

The findings were presented at the European Society of Cardiology Congress 2011 and simultaneously published online at bmj.com.

The Good Stuff in Chocolate

All of the studies reported overall how much chocolate people ate. The research didn't distinguish between dark or milk chocolate. Any source of chocolate counted, whether chocolate bars, chocolate drinks, or chocolate cookies, for example.

The studies showed how much chocolate people ate, from never to more than once per day. Participants were followed for eight to 16 years.

The components in chocolate that might explain chocolate's protective effects were not explored. Based on previous research though, the researchers credit what are called polyphenols, antioxidants that increase the body's production of the chemical nitric oxide.

An increase in nitric oxide production in turn might lead to improvements in blood pressure and blood flow though arteries.

"If we knew what components [exerted the healthy effects], we would package them in a pill," says past American Heart Association president Robert Bonow, MD, of Northwestern University in Chicago. He was not involved with the study.

Bonow tells WebMD that the study is "impressive" for its large size and the substantial reduction in heart disease and stroke associated with chocolate.

Still, the study doesn't prove chocolate lowers the rate of heart disease. The people who ate the most chocolate in the studies could share some other characteristics that explain their better heart and brain health.

"The good news is, it's not bad for you in appropriate quantities," Bonow says.

Franco notes that previous research suggests that dark chocolate may best for the heart.